Nematic, vector-multipole, and plateau-liquid states in the classical O(3) pyrochlore antiferromagnet with biquadratic interactions in applied magnetic field
Abstract
The classical bilinear-biquadratic nearest-neighbor Heisenberg antiferromagnet on the pyrochlore lattice does not exhibit conventional Néel-type magnetic order at any temperature or magnetic field. Instead spin correlations decay algebraically over length scales r≲ξc∼1/T , behavior characteristic of a Coulomb phase arising from a strong local constraint. Despite this, its thermodynamic properties remain largely unchanged if Néel order is restored by the addition of a degeneracy-lifting perturbation, e.g., further neighbor interactions. Here we show how these apparent contradictions can be resolved by a proper understanding of way in which long-range Néel order emerges out of well-formed local correlations and identify nematic and vector-multipole orders hidden in the different Coulomb phases of the model. So far as experiment is concerned, our results suggest that where long-range interactions are unimportant, the magnetic properties of Cr spinels which exhibit half-magnetization plateaux may be largely independent of the type of magnetic order present.
- Publication:
-
Physical Review B
- Pub Date:
- May 2010
- DOI:
- 10.1103/PhysRevB.81.184409
- arXiv:
- arXiv:1001.0270
- Bibcode:
- 2010PhRvB..81r4409S
- Keywords:
-
- 75.10.Hk;
- 75.80.+q;
- Classical spin models;
- Magnetomechanical and magnetoelectric effects magnetostriction;
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Statistical Mechanics
- E-Print:
- 27 pages latex, 25 eps figures